I wouldn't use anything high power from it. From what I've seen of the insides of this kind of socket, the actual contact area from socket to plug is usually much less than when the proper socket is used. It has to be as it's a compromise. You see this multipurpose 3 pin socket on Chinese inverters sold on eBay. It allows them to sell one model for all the 220-240V areas of the world.
There is also a relatively common two pin adaptor in this part of the world that has a socket accepting U.S flat pin plugs, and European and British round pin plugs. Despite having only two pins, 3 pin round pin and U.S plugs will fit but with the earth pin floating in mid air for all to see. Inside, the contacts are sort of a V shaped angle arrangement which takes care of different pin diameters and spacing. Problem is, it's only the edges of the pins which are held. Just the weight of the attached cable is often enough to make the plug fall out, to say nothing of plugpack transformers. One of these adaptors I have is actually a U.S flat pin to European round pin, but with the flat pins twisted to fit the Australasian socket. It gets used with fluorescent lead light I bought cheap at the markets (obviously without local approval).
